The present invention relates to systems and methods for protecting devices (switching and non-switching) such as micro electro-mechanical system (MEMS) and electronic relay devices in telecommunication systems. More particularly, the present invention is directed to circuit topology for protecting vulnerable MEMS and electronic relay devices due to lightning exposure or electrical power surges. The present invention can be implemented in telecommunication systems, which have direct physical connection to the outside copper wire plant such as telephony and/or DSL system equipment.
Micro electro-mechanical system (MEMS) devices and solid-state relays (SSR) have recently been developed as alternatives for conventional electromechanical switching devices such as relays. As is well known, the conventional devices possess some highly desirable characteristics such as low contact resistance, high voltage breakdown, and relatively high current handling capability, which characteristics make them ideal for use in telecommunication systems. However, a major drawback associated with such conventional devices is that they are not well suited for miniaturization or integration.
MEMS devices and SSR can perform the standard functions of conventional relays and are well suited for miniaturization and integration. MEMS devices are basically miniaturized electromechanical devices that are fabricated using techniques similar to those used for semiconductor integrated circuits and are well suited for low cost and high volume production. MEMS device applications have been used as pressure sensors, chemical sensors, light reflectors, switches, and relays. MEMS devices are low cost devices due to the use of microelectronic fabrication techniques, and new functionality may also be provided because they are much smaller than conventional devices.
However, the MEMS devices and SSR have several major shortcomings and disadvantages. The most notable disadvantage is that these devices are relatively fragile in current carrying and voltage breakdown capabilities. For example, because the MEMS devices and SSR are relatively fragile, lightning or AC power surges can completely destroy them. Lightning is characterized by very high voltage and current of very short duration pulses, i.e., less than 1.0 ms, whereas AC power surges or faults are characterized by very high voltage and current of relatively long duration pulses, i.e., seconds. As a result, systems having MEMS devices or SSR therein can become disabled and/or destroyed quite easily.
There are currently different systems and methods for protecting the MEMS devices and SSR from lightning and/or AC power surges. But, none of these conventional systems and methods is directed towards protecting the MEMS devices and SSR that are implemented within units such as cross connect systems, e.g., the xe2x80x9cCX 100 CrossConnect Systemxe2x80x9d from Turnstone Systems, Inc. The CX100 Copper CrossConnect System is a platform that automates the physical layer infrastructure in the central office, enabling ILECs (incumbent local exchange carrier) and CLECs (competitive local exchange carrier) to remotely control, test, and manage a copper loop. Additional information regarding Turnstone System""s CX100 Copper CrossConnect System can be found at its web site turnstone.com. It is also noted that other systems and units providing similar functionalities as the CX100 Copper CrossConnect System can be implemented in the present invention.
As stated above, the conventional systems and methods for protecting MEMS devices and SSR are found to be inadequate and unworkable in units such as those described above. Accordingly, there is a need for reliable and efficient systems and methods for protecting vulnerable MEMS and electronic relay devices due to lightning exposure or electrical power surges.
In view of the above-described problems of the prior art, it is an object of the present invention to provide systems and methods for protecting vulnerable MEMS and electronic relay devices due to lightning exposure or electrical power surges.
It is yet another object of the present invention to provide systems and methods limiting exposure to high voltages and currents to the MEMS devices and solid state relays.
It is a further object of the present invention to provide systems and methods for sensing a high current condition and thereby energizing a relay to protect the MEMS devices and solid state relays.
It is still a further object of the present invention to provide systems and methods for energizing a relay to protect devices (switching and non-switching) such as MEMS devices and solid state relays.
It is yet a further object of the present invention to provide systems and methods for monitoring the system after lightning exposure or electrical power surges.
It is another object of the present invention to provide systems and methods to protect metallic cross-connect systems implemented with MEMS devices and solid state relays.
These and other objects of the present invention are obtained by providing an over voltage protector and an over current protector in the units having devices such as the MEMS devices or solid-state relays. The over voltage protector is used to protect against fast rising voltage pulses such as lightning exposure, whereas the over current protector is used to protect against lower voltage than lightning exposure, but high current such as an electrical power surge. Accordingly, a relay is energized when a high current is sensed in the loop, which relay is used to protect devices such as the MEMS devices and SSR from damage. The relay can be controlled via software/hardware and works in conjunction with other components/devices in the overall system. The present invention can be implemented to protect any number of MEMS devices or SSR in a unit.